Abstract: Using an achiral ionic liquid, 1-butyl-3-methylimidazolium chlorine (［BMIM］Cl), as an additive and beta-cyclodextrin (β-CD) as a chiral selector, the enantiomers of chlorpheniramine, the precursor of chloramphenicol and ofloxacin were separated by capillary zone electrophoresis. This work was directed to the study of the association of ［BMIM］Cl to the chiral selector β-CD and the possible effects of ［BMIM］Cl on chiral separation. Simultaneously, the separation performances were studied when only containing β-CD in the buffer. The results showed that there are synergistic effects of ［BMIM］Cl as an additive for the enantiomeric separations. ［BMIM］Cl can not only remarkably increase the separation selectivity and resolution of the enantiomers, but also effectively restrain the adsorption of the sample molecules and improve the peak shape. ［BMIM］Cl as an additive of chiral separation can provide a new method for the separation of chiral drugs which are hard separable under common electrophoresis conditions.

Key words: beta-cyclodextrin (β-CD), capillary electrophoresis (CE), chiral drugs , chiral separation, achiral ionic liquid